Telephone-receiver



(No Model.)

J. E. FULLER.

TELEPHONE REGEIVER. No.- 322,884. Patented July 21, 1885.

i FEE,

' 1 INVENTOR ATTORNEY UNITED STATES PATENT OFFICE.

J. ENSIGN FULLER, OF CHICAGO, ILLINOIS.

TELEPHONE-RECEIVER.

SPECIFICATION forming part of Letters Patent No. 322,884, dated July 21, 1885.

Application filed April 9, 1884. (No model.)

To all whom it may concern:

Be it known that I, J. ENSIGN FULLER, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Telephone Receivers, of which the following is a specification, reference being bad therein to the accompanying drawings.

My invention consists of a multipolar magnet composed of several pole-pieces of a given polarity arranged in a group around a central re-entrant pole-piece of opposite polarity, said first-mentioned pole-pieces being attached to or integral with a disk or base or arms radiating from a common center, which forms the base of the re-entrant pole.

The object of my invention is to obtain more powerful magnetic action in a telephone-receiver than has heretofore been secured by other magnets, whatever their size or construction, and thereby greater amplitude of vibration in the diaphragm. Distinctness and clearness of the sounds reproduced is of the greatest importance, and these I secure by my instrument, so that vocal or musical sounds are readily heard and understood even when the'listener is several feet removed from the instrument. The loudest sounds as well as mere whispers are reproduced with equal distinctness, the sounds received varying only in degree. This function of my instrument I consider of the greatest advantage and practical utility, because it permits persons to carry on conversation in any tone of voice the circumstances may require.

In the drawings similar letters of reference indicate like parts.

Figure 1 is a sectional perspective view of my instrument, showingrthe arrangement of the several parts. Fig. 2 is a top view of the magnet with the case removed.

A A are the outside casing or box inclosing the entire apparatus.

O is the orifice through which the soundwaves reach the ear.

b b b b b b are pole-pieces of given polarity, together forming one pole of the magnet; and b is the other pole re-entrant or extended up inside of the other pole-pieces, and attached to or integral with the base, from which it is extended upward.

H is the helix or coil attached to the mentrant pole-piece, and having Wires f f leading to the line and ground.

0 isathin vibratory disk or diaphragm resting on pole-pieces b b b b b b. When the disk 0 is placed upon the upper end of the polepieces b b b b b b, said disk becomes one pole of the magnet,and the magnetism of said polepieces is concentrated directly over the reentrant or extended pole-piece b of opposite polarity. By thus bringing the poles of the magnet opposite to each other and in close proximity, greater magnetic strength is secured, as well as greater amplitude in the vibrations of the diaphragm.

I am aware that multipolar magnets in telephones, consisting of a series of separate U magnets arranged circumferentially and forming a compound central or re-entrant pole, have been used either with or without a central bar, and I do not claim such magnet as my invention.

I am also aware that magnets constructed substantially like mine have been used in telephones; but in such cases the diaphragm was not magnetized by contact with the circumferential pole-pieces, which is an important feature of my invention.

The essential feature of my invention is a multipolar magnet in which the pole-pieces arranged on the periphery of a circle are attached to or made integral with a base or disk,

or to arms radiating from a common center, with a single central pole-piece extending the opposite polarity of all of said pole-pieces up to a point slightly below a line drawn across the upper ends of such pole-pieces.

The advantage gained by my one re-entrant pole-piece is that the opposite polarity is thus centered in the smallest space possiblibeneath the diaphragm or other pole, and the diaphragm is acted upon at its absolute physical center.

Having thus fully described my invention, what I claim, and desire to secure by Letters Patent, is-

1. In a telephone-rece1ver,a multipolar magnet consisting of a number of pole-pieces of a given polarity attached to or integral with a base or disk, or arms radiating from a common center,carrying a plate or diaphragm ,and a re-entrant pole-piece of opposite polarity extending upward from said base or common center, substantially as described.

2. In a magneto-telephone, the combination of a multipolar magnet having circumferentially-arranged pole-pieces of one polarity pro- 10 jecting from a disk, and a single pole-piece of opposite polarity projecting from the center of the same, with a diaphragm resting upon the circumferential pole-pieces and in inductive proximity to the central pole-piece, sub- I 5 stantially as described.

3. In a magneto-telephone, the combination of a multipolar magnet having circumferentially-arranged pole-pieces of one polarity attached to or integral with arms radiating from a common center, and a single pole-piece of 20 opposite polarity secured to such common center or integral therewith, with a diaphragm resting upon the circumferential pole-pieces and in inductive proximity to the central polepiece substantially as described. 2 5 In testimony whereof I affix my signature in presence of two witnesses.

J. ENSIGN FULLER.

Witnesses:

JAMES P. FREEMAN, E. H. REEvEs. 

